Contribution to the Knowledge of Freshwater Shrimps (Crustacea, Decapoda) and Their Spatial Distribution in the Malebo Pool (Congo River), R.D Congo

Abstract

Background and Objective: Crustaceans play a considerable role in the ecological process of aquatic ecosystems, acting at different trophic levels as herbivores, detritivores, predators and prey and constitute an important source of animal protein for humans and livestock. This study investigated the diversity of shrimp from the left bank of the Malebo Pool in the Congo River.
 Study Area: Five sampling campaigns were organized from July 2020 to August 2021 in six sites (Ngamanzo 1, Ngamanzo 2, Kinkole 1, Kinkole 2, Kinsuka 1 and Kinsuka 2) in the Malebo Pool, the terminal part of the middle Congo River.
 Methods: Shrimp samples were collected using dip nets and creels during the experimental fisheries. Physical parameters were measured monthly in situ at six sites. Chemical parameters were assessed using an ultraviolet atomic spectrophotometer. Systematic identification of shrimp was done using appropriate systematic identification keys. The structure of the shrimp populations was studied using several ecological indices.
 Results: A total of 1422 shrimp specimens were sampled. These individuals belonged to three different species (Caridina africana Macrobrachium dux and Macrobrachium sollaudii), two genera (Caridina and Macrobrachium) and two families (Atyidae and Palaemonidae). Shanon and Weaver's diversity index values ranged from 0 to 1.3 indicating that the shrimp fauna is not diverse in Malebo Pool. These species are better represented at Ngamanzo 1, Ngamanzo 2 and Kinkole 2. Redundancy analysis (RDA) showed that environmental variables such as dissolved oxygen level, conductivity, water temperature, transparency, water flow velocity, plant debris, aquatic plants and canopy strongly influence taxonomic diversity across sites.
 Conclusion: The results obtained showed that the shrimp fauna is rich and diversified in the studied part of the Malebo Pool in the Congo River and, these organisms are essential in maintaining the ecological balance in this aquatic ecosystem.